Valve for closing a container, container and a system and method for filling container

ABSTRACT

A valve for closing a container and for enabling the container to be filled has a housing ( 20 ) with an inlet port ( 30 ) and an outlet port ( 40 ). A closing member ( 60 ) is provided for sealingly closing the valve at the inlet port ( 30 ). At least one valve member ( 70 ) is provided for controlling fluid communication between the inlet port ( 30 ) and the outlet port ( 40 ). The valve member only allows fluid communication when it is in a first position. The valve member ( 70 ) is designed in such a way that it is brought into and maintained in said first position only if a predetermined filling condition is achieved. The filling condition is typically achieved, when the filling pressure of a system for filling the container ( 50 ) is initially below a first predetermined or predeterminable threshold value.

The invention relates to a valve for closing a container, to a systemand a method for filling such a container with a fluid, and to acontainer. Containers such as cylinders containing a pressurised gas ora liquid or other receptacles are commonly used for storing anddispensing gases or fluids for both home and industrial uses. Often,there is a need to provide refilling systems for such containers.Particularly When such containers represent a substantial capital value,there is a need for refillable and returnable containers. There havebeen proposed many examples of such containers that can be refilled withnew content of gas or liquid after they have been emptied or have beenpartially used. Such containers can usually be easily refilled byproviding a gas or liquid at pressure into a filling and dispensingopening of the container. Typically, e.g. in the case of cylinderscontaining fluids under pressure, such containers have a dispensingvalve which is usually closed. This valve prevents leakage or theevaporisation of the fluid contents, that may be under pressure and/orvolatile. Such valves are designed to be selectively opened by a user.The valve is typically opened by depressing a pin to enable the contentsof the container to be dispensed or also to enable the container to befilled with a fluid.

One problem that may arise in the refilling of such containers is thatof ensuring that the containers are only filled with the correct fluidand that the fluid is provided only from authorised sources. Currentfilling systems can be duplicated relatively easily thereby enabling therefilling of a container by another fluid and/or by non-authorisedsources.

A typical example are CO₂ cylinders which are specially designed to fitinto machines requiring gas pressure, e.g. for soda-making machines.Such machines for home use can generally be filled from any suitable CO₂source. Thus, the provider of the original containers cannot ensure thatthe users will only go to that provider when the user desires to refillthe container. Similarly a fuel or gas container adapted to serve a homeor a number of apartments in a building may often be refilled by anysuitable fuel or gas source, without reference to the original providerof the container. Similarly, a gasoline or fuel station has containersthat can generally be refilled with any desired fluid and not just thespecific fuel designated for the containers and without reference to theoriginal provider of fuel or gasoline.

There have been some proposals for valves allowing selective filling ofa container.

U.S. Pat. No. 5,487,404 relates to a tap that stops a filling operationautomatically by means of a two-way valve. This tap is not directed tothe prevention of unauthorised filling of containers.

U.S. Pat. No. 4,195,673 is directed to increasing the difficultyaccompanying the dispensing of leaded fuel into a vehicle tank thatrequires unleaded fuel in systems where the nozzles used for dispensingleaded fuel is regulated to be smaller than the nozzles used fordispensing unleaded fuel. A magnetic collar is provided to the unleadedfuel nozzle, which interacts with a valve in a tank enabling the valveto open only when a dispensing nozzle carrying a magnet is inserted intothe fill tube. However, such arrangement only has one single sealingelement. Such an arrangement is especially difficult to be used incontext with fluid sources where the fluid is pressurised. A similarmagnetic seal arrangement is further shown in U.S. Pat. No. 5,474,115.

In U.S. Pat. No. 3,674,061, a nozzle arrangement in combination with avent are provided in such a manner that when the level in the tank beingfilled with a volatile liquid reaches a predetermined point, thepressure of gas in the tank suddenly increases to equalize with thedelivery pressure of the liquid. Sensing means sense the abrupt rise inpressure and a shut-off valve responsive to the sensing means cuts theflow through the delivery nozzle.

Prior art systems have several drawbacks: Especially, prior art systemssuch as systems for filling CO₂ bottles do not allow to ensure that thecontainer is only refilled by the original provider or via otherauthorised agents. This inability of the prior art may lead to alowering of the quality of the refill substances. The original providertherefore might be unjustly-associated with lower quality fluid becauseof the association of the original bottle with low quality fluid. Inaddition, the lack of control over refilling operations may alsoconstitute a source of danger and may lead to accidents and/or injuries,which could be prevented by appropriate filling of the container. Thelack of control over refilling operations may also constitute a loss inpotential income by the original provider.

WO 00/77442 relates to a refillable CO₂ gas cylinder and to a fillingdevice and a filling method. This document addresses a way to betterprotect a cylinder against being refilled by an unauthorised person. Forthis purpose, the document suggests a valve body, which forms a pistoncylinder unit together with an axially displaceable locking member. Thepiston cylinder can be impinged upon with a gas via an overflow channel.The locking member can be axially extended towards the interior where itbuts against a stop in the valve. Refilling without an appropriatefilling system shall be prevented. This solution, however, has certaindrawbacks. Mechanical means are provided in the filling device. Thesemechanical means must be used to hold open the locking member. It is,however, rather easy to overcome the function of the locking member byproviding suitable mechanical opening means.

It is therefore an object of the present invention to overcome thedrawbacks of the prior art, especially by providing a valve, acontainer, a system, and a method for filling such a container allowingthe original provider to ensure that refilling of the container is onlyconducted via themselves or other authorised agents. The systems shouldbe especially suitable for containers including pressurised gases in gasor partially liquid form.

The valve and the container as well as the system should be easy tomanufacture. According to a further object of the invention, the use ofa system and a valve according to the invention should not make thefilling or refilling of a container by an authorised user more difficultor more time consuming.

According to the present invention, these and other objects are solvedwith a valve, a container, a system, and a method for filling such acontainer according to the independent patent claims.

A valve for closing a container and for enabling the container to befilled comprises a housing. The housing is provided with an inlet portand with an outlet port. The inlet port is adapted to be connected to anappropriate fluid source. The outlet port is adapted to be connected tothe container. The connection between the inlet port and the fluidsource or the connection between the outlet port and the container canbe both, direct or indirect. Appropriate tubing could be provided formaking an indirect connection. The inlet port is connected to a fluidsource for filling or refilling the container with a content. The termsfilling and refilling are used interchangeably in the context of thisapplication. The inlet port can also be connected to an appropriatemachine for dispensing the content, e.g. to a soda machine.

The valve comprises a closing member for sealingly closing the valve.The closing member is used to keep the content within the containerunless dispensing of the content is desired by a user. The valve furtherhas at least one valve member. In a first position, the valve memberallows fluid communication from the inlet port to the outlet port. Whenthe valve member is in the first position, a container provided withsuch a valve can be refilled with a fluid. Fluid, as used in the contextof this application, includes gas, liquids or mixtures thereof. When thevalve member is in a second position, fluid communication from the inletport to the outlet port is prevented. The valve member is designed insuch a way that it is brought into and/or maintained in said firstposition only if a predetermined filling condition is fulfilled. Thevalve according to the invention on the one hand is used as aconventional valve for sealingly closing a container. On the other hand,the valve is used for preventing refilling of containers by unauthorisedpersons. Unauthorised persons who do not know that a specific fillingcondition must be fulfilled in order to open a passage between the inletport and the outlet port are unable to refill a container provided withsuch a valve.

According to the invention, the valve member is brought into andmaintained in said first position only if the static pressure differenceacross said valve member is below a predeterminable first thresholdvalue. The static pressure differential across the valve membertypically corresponds to the pressure difference between the inlet portand the outlet port. The valve automatically closes and thereforeprevents refilling of the container, if the filling pressure is toohigh. Especially when the valve is used on containers containingpressurised gases, the liquid provided by the fluid source has aconsiderable pressure. If conventional systems are used for refilling acontainer with a valve according to this aspect of the invention, thevalve will immediately close and will prevent refilling.

According to a preferred embodiment of the invention, the valve memberhas force-generating means. The force-generating means are adapted forproviding a balancing force to the valve member and for bringing thevalve member into the first position when the filling condition isfulfilled. There are different embodiments for such force-generatingmeans.

The force-generating means may be formed by a spring. The spring pressesthe valve member into said first position and maintains the valve memberin the first position. The spring e.g. moves the valve member away froma valve seat in a direction towards the inlet port. As soon as the forceacting on the valve member created by the pressure differential acrossthe valve member is greater than the force provided by the spring, thevalve is moved back and pressed against the valve seat. As soon as thefilling pressure of the fluid source becomes too high, the valve membercloses and filling of a container provided with such a valve isprevented.

According to another embodiment of the invention, the valve member isprovided with an internal part comprised in said valve. The internalpart can be operatively connected with an external part, which is notcomprised in the valve. When the internal and the external part are inoperative connection, the valve member is brought into and maintained inthe first i.e. open position.

There can be magnetic force-generating means. The internal part can e.g.be provided by a first magnet, which provides a balancing force in adirection directed towards the inlet port when the valve is brought intoproximity with an external part, which has a second magnet. Such asystem has an enhanced security. If conventional fluid sources are usedto refill a container with such a valve, the valve member will not bebrought into and maintained in the first position. At the latest whenrefilling of the container is started, the valve member is immediatelybrought into the second position, if no external part including anappropriate magnet is provided in connection with the fluid source. Asthe magnet only has a limited force to maintain the valve member in thefirst position, the valve member will be brought into the secondposition even if a magnet of an external part is present as soon as thefilling pressure of the fluid source exceeds a certain level. In orderto refill a container with such a valve, both an external magnet andappropriate filling pressure must be provided.

When the container is completely filled, the content of the container iskept in the container because of the closing member. The closing membermay be formed as a check valve. Check valves are commonly used incontext with pressurised gas cylinders. When the filling pressure issufficiently high, the check valve automatically opens and allowsfilling of the container. When the inside pressure of the container isabove the ambient pressure, the check valve closes and preventsevaporation or leakage or contamination of the content in the cylinder.For emptying the cylinder, the check valve must be opened by externalmeans, which are known to those skilled in the art.

According to a further embodiment of the invention, the check valve andthe valve member may be formed on the same body. The common body for thecheck valve and the valve member is movable in a chamber of the housingbetween the inlet and the outlet port.

In order to allow refilling of the container, the check valve maycomprise a pin attached to an end directed towards the inlet port. Whena user presses the pin, the check valve opens and allows filling oremptying of the container.

According to a further preferred embodiment of the invention, thehousing includes a chamber, which is divided into an upstream chamberand a downstream chamber. Downstream in the context of the presentinvention refers to a direction substantially along the direction offluid flow from the fluid source to the container, which is to befilled. The term upstream refers to a direction substantially opposedthereto. The upstream chamber is adapted for reciprocatinglyaccommodating the closing, member, e.g. the check valve. The downstreamchamber is adapted for reciprocatingly accommodating the valve member,which can be moved between the first and the second position within thedownstream chamber.

According to a further embodiment of the invention, the downstreamchamber is especially adapted to receive a valve member associated witha magnet as described above.

According to a further aspect of the invention, there is provided asystem for filling a container with a fluid exclusively from anauthorised fluid source. While the invention is especially suitable forfilling and refilling containers with pressurised gases such as CO₂, theinvention can be used for any type of fluid. In particular, theinvention is suitable for gases with a relatively high liquefactiontemperature or liquids having a relatively high vapour pressure. Inparticular, the invention is suitable for gases, which have vapourpressures that are substantially higher than ambient atmosphericpressure.

The system according to the invention comprises a pressure regulatingmeans. The pressure regulating means is in fluid communication to thefluid source. The pressure regulating means is further adapted for aconnection with a valve on a container as described above. The pressureregulating means is designed to maintain the pressure of the fluidsupplied to the container below a predetermined or a predeterminablesecond threshold. The second threshold is selected in such a way thatthe valve member of the valve is brought into and maintained in thefirst position during the filling procedure, i.e. such that the pressuredifferential across the valve member remains below the first threshold.

According to a preferred embodiment of the invention, the system can beprovided with fluid flow rate sensing means. The sensing means are usedto measure the flow of liquid into the valve and into the container. Thesystem further comprises control means operatively connected to thepressure regulation means and to the flow rate sensing means. If duringthe filling procedure, the delivery pressure of the fluid becomes toohigh, the valve member closes and filling is prevented. If the valvemember closes, the fluid flow rate sensing means detects that there isno fluid flow. By means of the control means, the delivery pressure ofthe system can be reduced such that the valve member will be againbrought into the first position.

According to still a further embodiment of the invention, the pressureregulating means is adapted for providing a delivery pressure of apredetermined minimum magnitude and for increasing the delivery pressurein a predetermined or in a predeterminable manner, e.g. in a mannercontrollable via said control means.

At the beginning of the filling process, the inside pressure in thecontainer in many cases is about similar to the ambient pressure. Thefilling pressure therefore should be above the ambient pressure andbelow the second threshold. The second threshold initially correspondsto the sum of the ambient pressure and the first threshold i.e. thelevel of pressure difference across the valve member at which the valvemember is moved into the second position.

When the inside pressure in the container reaches the filling pressure,the pressures equilibrate and refilling is stopped. At this moment, thecontrol means, initiate the pressure regulation means to increase thedelivery pressure. The increase is selected in such a way that the fluidflow rate remains within a predetermined range.

According to still a further embodiment of the invention, the system maybe provided with an external part which may be brought into operativeconnection with an internal part arranged within the valve as describedabove. According to this aspect of the invention, refilling of acontainer provided with the valve is only possible if an operativeconnection between the external part of a filling system and an internalpart of the valve is provided. There are a plurality of possible meansfor an operative connection, such as magnetic but also mechanicalconnecting means.

According to a further aspect of the invention, there is provided acontainer that has an opening closed with a valve as described above.The valve especially can be permanently attached to the opening of thecontainer, such that it cannot be removed from the container withoutdestruction of the container. In this way it is ensured that suchcontainers cannot easily be provided with different valves allowingrefilling with any known type of refilling system.

According to still a further aspect of the invention, there is provideda method for filling a container with a fluid from a fluid source. Themethod is especially adapted for filling a container having a valve asdescribed above. In a first step of the method, the valve attached to anopening of the container is connected to the fluid source. In a secondstep, the container is filled with said fluid whereby the deliverypressure of the fluid at an inlet port of the valve is controlled insuch a way as to keep the pressure difference across the valve member ofthe valve to remain below the predetermined or predeterminable firstthreshold.

During the step of filling, initially, there can be provided a staticdelivery pressure to said inlet port of the valve which is less than thesum of the ambient pressure and the first threshold. This pressure canbe provided for a predetermined or predeterminable period of time. Afterthis step, the delivery pressure can be increased in a plurality offurther steps or continuously. Because of the increased deliverypressure, no equilibrium between the delivery pressure and the internalpressure in the container is achieved until the desired final pressure,is reached.

According to a further preferred embodiment of the invention, the fluidflow rate is measured during the refilling or filling of the container.If the fluid flow rate is decreasing, the magnitude of the deliverystatic pressure is then increased by a predetermined step. The steps ofmeasuring the fluid flow rate and of increasing the delivery staticpressure are continued until the measured fluid rate is zero. A fluidrate of zero is an indication that an equilibrium between the maximumdelivery pressure of the fluid source and the content of the containerhas been reached as the delivery pressure cannot be increased above themaximum allowable pressure, i.e. the pressure of the fluid in the fluidsource. It is also possible that the increase of delivery pressure wastoo high and that the valve has closed before the desired internalpressure has been achieved.

According to a further embodiment of the invention this problem isavoided. The static pressure at the inlet port can be continuouslymeasured. If the static pressure is near to a predetermined thirdthreshold value, which is of the magnitude of the pressure of thecontainer when full, the filling operation is discontinued and the valveis disconnected from the fluid source.

If the static pressure measured is less than the predetermined thirdthreshold value, filling of-the container is discontinued. The pressurein the valve upstream of the outlet port is released and filling of thecontainer is resumed and filling is made as described above. Releasingof the pressure allows reopening the valve member.

This sub-step for distinguishing between the conditions is particularlysuitable for gases behaving substantially as ideal gases such as oxygenor nitrogen.

According to a further embodiment of the invention, the container may beweighed before and during the filling procedure. If the flow ratebecomes zero and if the weight of the container has not reached theexpected amount corresponding to a fully filled container, this is anindication that the container is not full.

The present invention is basically based on the idea, that a containeris provided with a valve preferably permanently connected to an openingof the container, wherein the valve can only be opened to allow thefilling of the container when the valve is connected to an authorizedfilling system, i. e. when predetermined filling conditions arefulfilled.

The invention will be better understood through the followingillustrative and non-limiting detailed description of preferredembodiments and with reference to the accompanying drawings, wherein:

FIGS. 1 a-1 c illustrate, in a cross-sectional transverse view, the mainelements of a valve according to a first embodiment of the presentinvention, in three different operating positions,

FIGS. 1 d and 1 e illustrate, in fragmented cross-sectional transverseview, an enlarged view of a closing member of the valve according toFIGS. 1 a-1 c in a static operating mode and in a dynamic operatingmode, respectively,

FIGS. 1 f and 1 g illustrate, in fragmented cross-sectional transverseview, an enlarged view of the valve member of FIGS. 1 a-1 c in a staticoperating and in a dynamic operating mode, respectively,

FIGS. 2 a-2 c illustrate, in a cross-sectional transverse view, the mainelements of a valve according to a second embodiment of the invention inthree different operating positions,

FIGS. 3 a-3 c illustrate, in a cross-sectional transverse view, the mainelements of a valve according to a third embodiment of the invention inthree different operating positions,

FIGS. 4 a-4 c illustrate, in a cross-sectional transverse view, the mainelements of a valve according to a fourth embodiment of the invention inthree different operating positions,

FIG. 5 illustrates schematically the main elements of the preferredembodiment of a system according to the present invention,

FIG. 6 illustrates schematically the main elements of a configuration ofthe pressure regulation means of FIG. 5,

FIG. 7 illustrates schematically the main elements of another embodimentof pressure regulation means of FIG. 5 and

FIG. 8 illustrates changes in delivery pressure with respect to time fora typical filling operation using a system as shown in FIGS. 5-7.

FIGS. 1 a-1 c illustrate a first and basic embodiment of the valveaccording to the present invention. The valve 10 comprises a housing 20with an inlet port 30 and an outlet port 40. A chamber 50 is definedbetween the inlet port 30 and the outlet port 40. The chamber 50 may bein any suitable form, including one or more interconnected cavities,conduits or the like such as to provide fluid communication between theinlet port 30 and the outlet port 40.

The upstream end of the housing 20 and particularly the inlet port 30 isadapted for connection to a suitable fluid source 600 (see FIG. 5).Connection may be made via a system 700 according to the presentinvention. The fluid source may include any suitable source such apressurized tank, a container or a fluid distribution system withoutbeing limited thereto. The downstream end of the housing 20 and inparticular the outlet port 40 is adapted for connection to a suitablecontainer 500 that is desired to be filled or refilled with a fluid fromthe source 600. Such a container is typically in, but not limited to theform of a pressurizable cylinder. The container 500 comprises acontainer inlet 520 and a holding volume 550 for the fluid. The housing20 of the valve 10 is preferably adapted for permanent connection to anopening of the container 500. It can be formed integral therewith,welded thereto, bonded thereto or otherwise permanently joined thereto.A reversible connection, which can be useful for maintenance or repair,is also conceivable. In either case, when connected to the housing 20, afluid communication is established between the holding volume 550, thecontainer inlet 520 and the outlet port 40 of the valve 10.

The housing 20 comprises a closing member in the form of a closingmember 60 that is reversibly movable, typically reciprocatingly, betweena closed upstream position and an open downstream position. The closingmember 60 comprises a face seal 61 at an upstream end thereof thatsealingly abuts a valve seat 21 comprised in an inner part of thehousing 20 at the inlet port 30 when it is in the upstream position.This position is shown in FIG. 1 a. For dispensing fluid from thecontainer 500 via the valve, a pin or a similar device may be insertedinto the inlet port 30 to depress the closing member 60 in a downstreamdirection. Alternatively, the first valve may be provided with a pin(not shown) projecting through the inlet opening 30. In the downstreamposition, the face seal 61 is distanced from the valve seal 21 (see FIG.1 b). Thus, fluid communication between the inlet port 30 and thus afluid source connected to the inlet port and the chamber 50 in the valve10 is allowed.

Optionally, a suitable downstream stop 25 may be provided in the housing20, placing a limit on the downstream position. The closing member canhave any position from a minimally opened position just enabling fluidcommunication to the maximum open position illustrated in FIG. 1 c,where the closing member 60 is against the stop 25.

The closing member 60 comprises an upstream face 62. Upstream face 62may include a face seal 61. Delivery static pressure P1 from the system700 acts on to the upstream face 62. The sealing assembly 60 further hasa downstream facing surface 63 on which the chamber static pressure P2is acting.

The face 62 comprises a protrusion 66 which may have a closed shape suchas a circle over the surface of the face 62. The protrusion 66 definesthe sealing perimeter of the face seal 61 with respect to a valve seat21. Under static conditions, the effective area of the face 62 is givenby the enclosed area A1 bounded by the protrusion 66. It is usually lessthan the corresponding area A2 of the surface 63 (see FIGS. 1 a-1 g).

The condition for the closing member to open is that the downstreamforce F1 given by the product of the delivery pressure P1 and theeffective area A1 is greater than the upstream force in the chamber 50.The upstream force F2 is given by the, product of the chamber pressureP2 and the area A1. Once the closing member 60 is open and dynamicconditions exist, the effective area A1′ of the face 62 becomes equal tothe area A2 (see FIG. 1 e).

The closing member 60 is configured to move to the open downstreamposition responsive to a first force F1 of a minimum magnitude appliedthereto. The minimum magnitude corresponds to a positive fluid staticpressure difference ΔP1 (P1−P2), which exists between the inlet port 30and the chamber 50. The pressure difference may be generated during theoperation of the valve 10 after the initial opening force F1 provided bya sufficiently high delivery pressure P1≧P2. The closing member moves tothe closed upstream position corresponding to a positive fluid pressuredifference existing between the chamber 50 and the inlet port 30.Optional urging means (not shown) such as a coil spring may be providedto urge the closing member towards the closed upstream position.

The value of P2 will generally depend on the downstream back pressure P3provided by the container. As the container fills up with fluid, P3 willincrease and P2 will tend to equalise with P1. However, once the firstclosing member 60 is fully open, the pressure P2 is still below P1 dueto the restriction caused by inlet port 30, whether the fluid flowingtherethrough is in the gaseous or liquid state.

The housing further comprises a valve member 70 which is reversiblymovable, typically reciprocatingly, between a first, open, upstreamposition and a second, closed, downstream position. The valve member 70comprises a face seal 71 at a downstream end thereof that sealinglyabuts a valve seat 22 comprised in an inner part of the housing 20 atthe outlet port 40 when the valve member is in the second downstreamposition (see FIG. 1 c). In the first upstream position (see FIG. 1 b)the face seal 71 is distanced from the valve seat 22 and allows fluidcommunication between the chamber 50 and the outlet port 40 and thusalso between a container 500 connected to the outlet port 40. A suitableupstream stop 26 which can be integral with the downstream stop 25 maybe provided in the housing 20 and place limit on upstream travel of thevalve member 70. The first position can include any position fromminimally opened to the maximum open position shown in FIG. 1 a.

The valve member 70 comprises an upstream face 72 on which acts chamberstatic pressure P2 and a downstream facing surface 73 which may includea face seal 71, on which acts the back static pressure P3 from thecontainer 500. The face 72 has a protrusion 76 typically in the form ofa closed shape such as a circle over the surface of the face 72 todefine the sealing perimeter of the face seal 71 with respect to thevalve seat 22. Under static conditions, the effective area of the face73 is given by the enclosed area A3 bounded by the protrusion 76 and isgenerally less than the corresponding area A2 of the surface 73. Thecondition for the valve member assembly 70 to open is that the upstreamforce F3 given by the products of the back pressure P3 and the effectivearea A3 plus a balancing force provided by force-generating means 80 isgreater than the downstream force F2 in the chamber 50 given by theproduct of the chamber pressure P2 and the area A3. When the valvemember 70 is open and dynamic conditions exist, the effective area A3′of the lower face 72 becomes equal to the area A2.

The valve member 70 is thus configured to move to said second positionresponsive to a third force P3 of predetermined minimum magnitude thatmay be applied to the valve member 70 corresponding to a second positivefluid static pressure difference ΔP3 (=P2−P3) that may exist between thechamber 50 and the outlet port 40, generated for example duringoperation of the valve 10.

When both, the closing member 60 and the valve member 70 are open, fluidflows from the fluid source to the container since the pressuredifference P1−P3 is positive. The pressure P2 is still greater than P3due to the restriction caused by outlet port 40 and due to the fact thatthe container 500 takes time to fill and does create the back pressureequal to P2, whether the fluid flowing therethrough is in the gaseous orliquid state. When the container is full of liquid, then P1, P2 and P3equalise and no more fluid flow is possible.

Alternatively, the face seal and the valve seat arrangement for theclosing member 60 and the valve member 70 may be replaced with othertypes of known sealing arrangements. While the closing member 60 and thevalve member 70 are illustrated in FIGS. 1 a-1 c as reciprocatable alonga common axis, the longitudinal axis 100 of the valve 10, each one ofthe closing and the valve member 60, 70 may move along axis which arenot mutually co-aligned and/or that are not aligned with the axis 100 ofthe valve 10.

The valve 10 further comprises at least a part of a suitableforce-generating means 80. The force-generating means 80 provides abalancing force Fx to the valve member 70 at least during operation ofthe valve 10. The force-generating means may be comprised in itsentirety in the housing and thus continuously provide the requiredbalancing force Fx. It may e.g. be in the form of a coiled spring.Alternatively, the force-generating means 80 may be only partiallycomprised in the valve 10 and in the housing 20. A complementary part(see eg. FIG. 5) of the force-generating means 80 can be providedexternally to the valve 10 only during operation of the valve 10 with acompatible and authorized filling system 700.

When a nominally empty suitable container 500 is connected to the outletport 40 such as to provide fluid communication there between, threedifferent scenarios are possible for the valve 10:

-   -   a) The container 500 may have a residual pressure, i. e. the        container is not completely empty. In this case, the residual        pressure maintains the closing member 60 in the closed position        as shown in FIG. 1 a. The valve member 70 may be urged to the        first position responsive to the balancing force Fx provided by        the force-generating means 80. If this force Fx is absent, the        valve member 70 may comprise any position within the housing 20.        This scenario a) may be routinely avoided by venting the        container 500 prior to refilling thereof.    -   b) The container may be at ambient pressure. The closing member        60 is typically in the open position. It probably abuts the stop        25. The valve member 70 may be urged to the first, open position        responsive to the balancing force Fx provided by the        force-generating means 80. If the balancing force is absent, the        valve member 70 may comprise any position in the housing 20,        typically the second position.    -   c) Rarely, the container 50 may be at a lower pressure than        ambient pressure, e.g. when the container has been emptied at an        altitude with low ambient atmospheric pressure and when it is        desired to refill-the container at a lower altitude. In this        situation, the closing member 60 is in the open position and        abuts the stop 25. If the force-generating means 80 is providing        the balancing force Fx, this will be sufficient to overcome the        vacuum effect and to open the valve member 70 until pressure        equalizes between the container 500 and the ambient atmosphere.        If the force Fx is absent, the valve member 70 will remain at        the closed second position. In such a case, the balancing force        Fx must be generated to permit equalization of the pressures.

When an unauthorized fluid source is connected to the valve inlet port30, the relatively large fluid delivery pressure associated with suchknown sources generates a relatively large first force F1 opening theclosing member 60 and abutting the same against the stop 25. Almostsimultaneously, the same high delivery pressure P2 provides a largesecond force F2 to the valve member 70 due to the relatively largepressure difference with respect to the pressure P3 within the container500. The only force available to counter the large second force F2 isthe balancing force Fx provided by the force-generating means 80. If themagnitude of the force Fx is chosen such that it is to small to counterthe force F2 in cases other than when there is a small static pressuredifference across the valve member 70, the valve member 70 is moved intothe closed position.

If it is attempted to fill the container 500 at a constant deliverypressure of a low magnitude, the filling process will end as soon as thepressures are equalised. The container will only be partially filled. Anunauthorised user attempting to fill the container by manuallyincreasing the delivery pressure to keep the valve open will havedifficulties to precisely control the delivery pressure. Finecontrolling would inevitably require an extremely lengthy time periodand such unauthorised user may be generally deterred.

If the valve 10 only comprises an inner part of force-generating means,no balancing force Fx is provided unless the activity of thecomplementary external part 80′ is duplicated by an unauthorised user.The valve member 70 will therefore shut. This applies when the valve 10and the-container are in scenario b) or c). In scenario a), either thereis no flow because the delivery pressure is less than or equal to theresidual pressure in the container. If the delivery pressure is greaterthan the residual pressure, the pressure difference will immediatelyclose the valve member if no balancing force Fx is provided.

The fluid filling system 700 according to the invention is adapted forcontrolling the delivery pressure of the source 600 (see FIG. 5) atleast just upstream of the valve inlet port 30. Filling is started witha very low delivery pressure. The delivery pressure is incremented in apredetermined manner. Essentially, starting at a low delivery pressure,the static pressure in the chamber 50 is also low and thus ΔP1 is small,giving rise to a small force F1 sufficient to open the closing member60. The closing member 60 may also be kept in the open position by meansof a mechanical pin or equivalent not shown in a similar manner to thatused when it is desired to dispense fluid from the container 500.

Although at this point, the static pressure P2 in the chamber 50increases as the fluid flows therethrough into the container, thedifference in static pressure ΔP3 or P2−P3 between the chamber 50 andthe container is small and the downstream force F2 generated thereby onthe valve member 70 is counteracted by the balancing force Fx. Themagnitude of the balancing force Fx is chosen according to the type offluid in, the source 60 and to the mechanical characteristics of thevalve 10. If the delivery pressure from the source 600 at the inlet port30 is even a little higher than a nominal starting value, ΔP3 will begreater than aforesaid and will generate a downstream force F2 which isgreater than the balancing force Fx, causing the valve member 70 to moveto the second position and thus to close the valve 10. As fluid flowsthrough valve 10 into the container 500, the static pressure P3 of thecontainer 500 begins to increase and thus eventually would equalise withthe delivery pressure P1. This would result in the container 500 beingpartially filled until the pressure equalises. If an unauthorised userwishes to circumvent the system 700 by providing a very low deliverypressure, the low amount of fluid that can be provided would act asdeterrent for such unauthorised use.

According to the invention, the fluid filling system 700 is adapted forincrementally increasing the delivery static pressure P1 at the inletport 30 such as to maintain the pressure difference across the valve,i.e. P1−P2, and therefore ΔP3 substantially constant in registry withthe increasing back pressure P3 of the container 500, the value of ΔP3being that to provide a force substantially equal to the balancing forceFX. In other words, the system 700 first provides a very low deliverystatic pressure to the inlet port 30 and thus to the chamber 50, and asthe back pressure from the container 500 increases due to accumulationof fluid therein, the delivery pressure P1 is increased in a controlledmanner such as to maintain ΔP3 constant, correlated to the value of thebalancing force Fx. Only if a complimentary and authorised fillingsystem 700 is used, it is possible to completely fill the container 500within a reasonable time frame.

Instead of the embodiments shown in FIGS. 1 a to 1 g, differentconstructions of the valve are conceivable whereby the valves operate asdescribed above. According to the second embodiment shown in FIGS. 2 ato 2 c, the closing member and the valve member are integrated into asingle combined valve assembly 260. The valve sealing assembly 260comprises a face seal 261 at an upstream end that sealingly abut a valveseat 221 comprised in an inner part of the housing 220 at the inlet port30, when in a closed upstream position (see FIG. 2 a). For dispensingthe fluid from the container 500 via the valve 210, the valve assemblytypically comprises a pin 290 that projects through the inlet opening30. By depressing the pin 290, the assembly 260 is moved to open theinlet port 30. In the open downstream position (see FIG. 2 b) the faceseal 261 is distanced from the valve seal 221 and allows fluidcommunication between the inlet port 30 and the chamber 250. Theassembly 260 comprises a face seal 271 at a downstream end thereof whichsealingly abuts a valve seat 222 comprised in an inner part of thehousing 220 at the outlet port 40 when it is in the closed position asshown in FIG. 2 c. In the position shown in FIG. 2 b, the face seal 271is distanced from the valve seal 222 and allows fluid communicationbetween the chamber 250 and the outlet port 40. The container can befilled when the assembly 260 is in the position shown in FIG. 2 b. Theassembly 260 has an upstream face 262 on which acts delivery staticpressure P1 from the system 700 and a downstream facing surface 273 onwhich acts the back static pressure P3 from the container 500. Theeffective areas of the faces 262 and 273 are substantially the same whenthe assembly 260 is open and is operating dynamically. According to thisembodiment, the force-generating means comprises a spring 280, typicallya helical a spring, which abuts at its upstream end a spigot 270 thatdepends in a downstream direction from the valve assembly 260 and whichabuts at its downstream end a suitable shoulder 285 comprised in thehousing 220. When depressed, the spring 280 stores elastic potentialenergy and provides a restoring or a balancing force Fx in the upstreamdirection to the valve assembly 260. When the force F1 provided as aresult of the pressure difference between the inlet port 30 and theoutlet port 40 is to large, e.g. when it is attempted to fill thecontainer 500 without using an authorised system, this relatively largeforce overcomes the resistance of the spring 280, which compresses intorecess 286 enabling the valve assembly 260 to move to a closed positionso as to close the outlet port 40 (FIG. 2 c).

Such springs can be used with a valve member different from the oneshown in FIGS. 2 a to 2 c.

A valve according to a third embodiment of the invention is shown inFIGS. 3 a to 3 c. It comprises all elements of the first embodiment ofthe valve 10 as described above with the differences described hereinbelow whereby like parts have like reference numerals increased by 300.The valve 310 comprises a housing 320 with a chamber 350, which isdivided into an upper sub-chamber 351 and a lower sub-chamber 352. Theupper sub-chamber 351 comprises a closing assembly 360 movable therein.The lower sub-chamber 352 comprises the valve member 370 movabletherein. The closing member 361 is formed in a similar way as in thesecond embodiment. Optionally, the closing member 360 may comprise arestoring spring 374 which abuts at its upstream end a spigot 376 thatdepends in a downstream direction from the closing member 360 and whichabuts at its downstream end a suitable shoulder 385 comprised in thehousing 320. The restoring spring 374 urges the closing member 360 intoa closed position even when the static pressure in the valve 310 is notgreater than the external pressure and the force generated by the spring374 is generally lower than the magnitude of first force F1 at least atthe beginning of the filling process. When the spring 374 is fullycompressed, there is still a fluid communication between the upper subchamber 351 and the lower sub-chamber 352 (see FIG. 3 c). Spring 374 isprovided to ensure that the container 500 is closed after it has beencompletely emptied in order to avoid contamination of the interior ofthe container 500.

According to this embodiment, the force-generating means 80 comprise aninternal part 380″ comprised in the valve 310 and a complementaryexternal part 380 that is typically comprised in the system 700according to the invention. The internal part 380″ is in the form of amagnetic element 381 comprised in the valve member 370. In FIGS. 3 a to3 c, the magnetic element 381 forms the main body of the valve member370. It is reciprocatable in the lower sub-chamber 352 which may haveits axis 200 orthogonal with respect to the longitudinal axis 100 of thevalve 310. The magnetic element 381 may also be separate to and includedin the valve member 370. The magnetic element 381 is arranged such as tohave a particular pole, e.g. its north pole, facing towards the outsideof the housing 320 and thus typically also away from the axis 100 of thevalve 310. The magnetic element 381 is arranged aligned with the axis200 of the lower sub-chamber 325. The complementary part 380′ alsocomprises a magnetic element 382. If the complementary part 380″ of theforce-generating means is brought into proximity with the valve 310 suchthat similar poles are facing each other as shown in FIGS. 3 a to 3 c,the external part 380 has its north pole facing the north pole of themagnetic element 381. The balancing force Fx in this embodiment isprovided by the magnetic repulsion between the magnetic elements 381 and382, which serves to urge the face seal 361 away from the valve seat322. If it is attempted to use the valve 310 with a system 700 withoutan external part 380′, no balancing force Fx will be generated and thevalve member 370 is free to move back to a closed position. As soon asthe inlet port 30 of the valve 310 is exposed to a delivery pressureabove the static pressure in the container 500, the valve member 370closes the outlet port 40.

The valve according to the forth embodiment of the invention shown inFIGS. 4 a to 4 c comprises all the elements of the first embodiment ofthe valve 10 with the difference described herein below. Referencenumerals increased by 400 refer to similar parts as in the thirdembodiment. The, downstream end of the spring 474 is accommodated in asuitable well 485 comprised in the housing 420 as compared to theaccommodation of the down-stream end of the spring in the thirdembodiment. The main difference between this embodiment and the thirdembodiment is, that in this embodiment the force-generating means 80operates by means of magnetic attraction between two elements, ratherthan by magnetic repulsion. The internal part 480″ in the forthembodiment may be in the form of a magnetisable element 481 comprised inthe second valve member 470. It may comprise a ferrous core and form themain body of the valve member 470. During proper operation of the valve420, a complementary part 480′ of force-generating means 80 is broughtinto proximity with the valve 410 such that one of the poles of themagnetic element 482 is aligned with the axis 300 of the valve member470. The balancing force Fx in this embodiment is provided by themagnetic attraction between the magnetic element 482 and themagnetisable element 481. The operation of the valve according to theforce embodiment is similar to the operation of the valve according tothe third embodiment. Alternatively, the internal part 480″ of theforce-generating means 80 may comprise a magnetic element with its polesarranged such as to provide a magnetic attraction force when brought inoperative connection with an external part 480′ of the filling system700.

As mentioned above, the force-generating means 80 is calibrated toprovide a suitable balancing force Fx of a magnitude that is chosenaccording to the fluid being used in conjunction with the valveaccording to the invention. When the fluid is a liquid with lowevaporation point, such as petrol and the like, or a gas with lowliquefaction point, for example carbon dioxide, it quickly forms aliquid deposit in the container 500 which is otherwise filled with thegaseous or vapour phase of the liquid, which in turn provides aforesaidback pressure P3.

This back pressure generally depends on the nature of the fluid and thetemperature thereof and varies from fluid to fluid. As soon as someliquid forms in the container the vapour pressure remains constant asmore liquid forms, so long as the temperature remains constant. Inpractice, however, the expansion of the gas into the container 500results in the cooling thereof and thus in a lower vapour pressure thanat ambient temperature. As the container 500 is filled some more and thetemperature stabilises and begins to increase, the vapour pressuresimilarly increases and eventually stabilises being a function of thetemperature in the container 500 and independent of the level of liquidphase therein so long as some minimum quantity thereof exists therein.

Essentially, then, for all embodiments, the valve member remains openduring filling operation of the container when the positive pressuredifference between the delivery fluid pressure P1 and the containerfluid pressure P3 (that is the positive pressure difference ΔP13 betweenthe first and/or the second end of the valve) is not greater than aparticular value such that the causing force acting on the valve membercorresponding to the pressure difference may be countered by the balanceforce Fx and does enable the valve to remain open.

Thus for a given fluid delivery pressure, the value of Δp13 will vary,according to the particular vapour pressure of the fluid. Since themagnitude of the balancing force Fx is related to Δp13, account must betaken of the nature of the fluid when choosing Fx. Thus, for example, ifa valve in which the force-generating means 80 provides a particularbalancing force that is appropriate for carbon dioxide, that has arelatively large vapour pressure, is used for filling a container 560with a fluid of lower vapour pressure, the balancing force Fx would beinsufficient to maintain the second valve assembly 70 open. This isbecause the magnitude of Δp13 provided by the system would result in aforce that is larger than Fx, causing the corresponding valve member toclose. On the other hand, if it is attempted to use the same valve witha fluid having substantially higher vapour pressure than the nominalvalue for the valve, than the valve can still operate.

On the other hand, gases with very low liquefaction point, such as O₂,N₃ and so on, behave more or less as ideal gases, and thus the backpressure will continually increase as the delivery pressure increases.

The valve according to the present invention is therefore adapted tooperate, i.e., to enable a container attached thereto to be filled, onlyunder specific conditions:

-   -   a) that a suitable balancing force Fx is present at least during        filling of the reservoir, and    -   b) when the delivery pressure P1 at the inlet port of the valve        begins at a specific very low magnitude and is subsequently        increased in a manner such as to provide a closing force to the        valve member that is not greater than the balancing force        generated by the force-generating means of the valve, as the        back pressure P3 from the reservoir increases.

Accordingly, the fluid filling system 700 according to the inventioncomprises the features necessary to provide these conditions.

Thus, and as illustrated schematically in FIG. 5, a preferred embodimentof the fluid filling system 700 of the present invention comprises asuitable pressure regulating means 720 operatively connectable to thefluid source 600, and a suitable fluid flow rate sensor means 730operatively connected to the pressure regulating means 720 andoperatively connectable to the valve 10 according to the invention.While the valve 10 according to the first embodiment of the invention isschematically illustrated in FIG. 5, the description of the system 700is similarly applicable to other embodiments of the valve, mutatismutandis. The system 700 further comprising suitable control means 710operatively connected to the pressure regulating means 720 and to thefluid flow rate sensor means 730, and provides control of the pressureregulating means 720 according to the fluid flow rate measured by thefluid flow rate sensing means 720.

According to the type of valve 10 used with the system 700, the system700 may also comprise a complementary external part 80′ of saidforce-generating means 80 such that when the valve 10 is operativelyconnected to the system 700, and at least when the system 700 is inoperation, an appropriate balancing force Fx is generated in the valve10.

The pressure regulating means 720 comprises any suitable pressureregulator arrangement capable of delivering a delivery fluid pressure P1that is initially very low at its output, regardless of the magnitude ofthe fluid pressure of the fluid source 600 connected thereto. Further,the pressure regulating means 720 is capable of being finely controlledsuch as to increase the output fluid pressure thereof in very smallsteps. Such steps may be optimised, since steep changes in pressure withrespect to time may result in the valve member closing, while shallowchanges in pressure with respect to time reduces the filling efficiency,resulting in long refill time for the container 500. One optimumpressure change rate found by the applicants for filling a reservoirwith CO₂ is about 4 bars in 2 seconds.

Optionally, and as illustrated in FIG. 6 the pressure regulating means720 may comprise a pressure regulator 810, that is connectable to thesource 600 via any suitable conduit and/or connectors 805. An airpressure source 830 provides air at a predetermined high pressure to aproportional valve 840, which is operatively connected to the controlmeans 710 via communication line 845, which serves as an additionalpressure regulator that can be used to operate the pressure regulator810. Such an arrangement may be useful when off the shelf components forthe elements in FIG. 6 provide the required control over the deliverypressure, which in turn is in fluid communication with the pressureregulator 810. When the control means 710 determines that an increase indelivery pressure is required from the pressure regulating means 720, anappropriate signal is sent to the proportional valve 840 which thenincreases its output pressure with respect to the cylinder 850 which inturn opens the pressure regulator 810 such as to provide the desireddelivery pressure to the valve 10. The control means operate in a mannerknown to those skilled in the art.

One advantage in using the pressure regulating means 720 of FIG. 6 isthat a sufficiently sensitive and controllable pressure regulation maybe provided using off the shelf components.

Optionally, and typically the system 700 further comprises suitablescales 770 or other weighing means for determining the mass or weight ofthe container 500 at least before the filling procedure and at the endthereof, to ensure that the container has been filled with the requiredamount of fluid. Preferably, the scales 770 enable the weight or mass ofthe container to be continually monitored during the filling operationand advantageously, the scales 770 are operatively connected to thecontrol means 710 and are adapted for transmitting thereto a signalrepresentative of the weight or mass of the container 500. Thus, thecontrol means 710 continually monitors the weight or mass of thecontainer 500 during the filling procedure. This has the advantage thatif the second valve sealing means closes while the container is not yetfull or within a proportion thereof, say 98% full as indicated by thelow weight of mass value provided from the scales 770 to the controlmeans 710 this indicates that the delivery pressure was too high ratherthan the container is full. Thus, this configuration enables the controlmeans 710 to distinguish between a situation where the container is fullto one where the cause of the valve member closing is high deliverypressure. In this case, flow rate sensor 730 could also be omitted.

Alternatively, and as illustrated in FIG. 7, the pressure regulatingmeans 720 may comprise, as before, a pressure regulator 810 such as forexample, that is connectable to the source 600 via any suitable conduitand/or connectors 850. However, the pressure regulator 810 is connectedto a suitable stepper motor arrangement 860 that is adapted to enablethe pressure regulator 810 to increase or decrease the delivery pressurein small steps correlated to the stepping action of the motor 860. Suchstepper motors 860 are well known in the art. The stepper motor 860 isoperatively connected to the control means 710 via communication line845. When the control means 710 determines that an increase in deliverypressure is required from the pressure regulating means 720, anappropriate signal is sent to the stepper motors 860, which then rotatesby the required number of incremental steps, which in turn opens thepressure regulator 810 by a corresponding amount such as to provide thedesired delivery pressure to the valve 10.

Advantages in using the pressure regulating means 720 of FIG. 7 includethat a sufficiently sensitive and controllable pressure regulation maybe provided using off-the-shelf components, and that less components arerequired relative to the arrangement of FIG. 6.

The fluid flow sensing means 730 comprises any suitable fluid flowsensor or sensors capable of sensing and measuring fluid flow rates,either mass flow rate or volume flow rate or both typically from verysmall values such as for example a few standard cubic centimeters (sccm)to nominal flow rates including for example a few standard liters persecond, and to detect small changes in the flow rate. Further the flowrate sensing means is capable of converting the fluid flow rate measuredthereby into appropriate signals, typically electrical or electronic,either analogue or digital, capable of being received and processed bysaid control means 710. The fluid flows sensing means typically comprisea flow meter. Suitable flow meters are known in the art. Such flowmeters typically provide RPM of a turbine comprised therein as afunction of the flow rates passing therethrough.

The control means 710 typically comprises a micro-processor basedcontrol system, such as for example a computer externally connected tothe system 700, or alternatively, and preferably, a suitablemicroprocessor chip integrally comprised in the system 700. Inparticular, the control means 710 is adapted for receiving suitablesignals from the fluid flow sensing means 730 and based on these signalsto provide control signals to the said pressure regulating means 720 tocontrol the delivery output pressure P1 provided thereby.

The system 700 is normally integrally or permanently connected to asuitable fluid source 600 via the pressure regulating means 720 butcould be removably connected thereto, for example to facilitatemaintenance of the source 600 or system 700. When it is desired to filla container 500, the system 700 is connected to a valve 10 (which istypically, permanently connected to container 500) via the fluid flowrate sensing means 730. Alternatively, the flow sensing means 730 may beconnected to the fluid source 600, and the pressure regulating means 720may be connected to the valve 10 mutatis mutandis. At the start of anormal filling operation of the system 700 the control means 710commands the pressure regulating means to provide a delivery pressure P1of relatively very low magnitude, such as to provide a differentialpressure Δp13 that generates a force to the valve member that is notgreater than the balancing force Fx provided by the force-generatingmeans 80. Since the control means 710 is calibrated for a specific typeof valve 10 the precise starting delivery pressure P1 that is requiredfor operating the valve 10 is known.

Optionally, the control means 710 may be programmed for use with aplurality of valves 10 and/or for use with a multitude of differenttypes of valves, and thus may control each valve 10 separately orsimultaneously in a similar manner to that described herein, mutatismutandis.

If at the start of the filling procedure the flow rate sensing means 730measures a zero flow rate, this is indicative of scenario a), i.e., thatthe container has a residual pressure, and thus that the deliverypressure is insufficient to open the closing member 60, the container500 can be removed, emptied and connected to the system 700 via valve10. Alternatively, mechanical means such as a suitable pin arrangementmay force the closing member 60 to open when the valve is connected tothe system 700. Alternatively, and preferably, a suitable blow-off orpressure release valve 740 may be used to bleed the container 500 priorto use, as will be further described herein below.

Typically, particularly in scenario b), a small fluid flow rate will beinitially detected by the fluid flow rate sensing means 730 at thebeginning of operations. As marked G in FIG. 8, delivery pressure P1typically starts at nominally zero, increasing rapidly until a backpressure P3 is detected, limiting P1 such that the positive pressuredifference does not exceed Δp13. Referring to fluids such as CO₂ thathave relatively high liquefaction points. As the container 500 begins tofill with fluid, the static pressure P3 in the container 500 increasesand this part of the filling operation is marked A in FIG. 8, whereinthe fluid is exclusively in the gaseous phase in container 500.

The increase in delivery pressure P1 with respect to time, may beoptimised so that on the one hand it is not too high A′ resulting inclosure of the valve member, and not too low A″ resulting in a longrefill time. Preferably, the positive pressure difference Δp13 is keptconstant and less than or equal to a pressure difference with respect towhich the balance force Fx is calibrated. Eventually, liquid begins toform in the container 500, marked B in FIG. 8, and the fluid deliveredvia the valve comprises an increasing proportion of liquid with respectto the gaseous phase. Accordingly it is possible to increase the rate ofchange of delivery pressure P1 with time to a new value, to decrease thefilling time, maintaining however the same pressure difference at leastor equal to Δp13. At a certain point when a predetermined amount ofliquid is formed in the container, for example when the net weight ofthe contents has reached 50 g, the system increases the rate of changeof pressure to still a higher value, again maintaining the pressuredifference across the valve at least or equal to Δp13. When a criticalamount of liquid has been deposited in the container, such that thevapour pressure is constant (the temperature also having stabilised),thereafter there is a more or less constant vapour pressure as morefluid is provided to the container, marked C in the figure. Thereafterthe delivery pressure P1 is kept constant at the value corresponding tothe vapour pressure plus Δp13 marked C in the figure. Typically fluidflow is terminated when the net weight of the container contents reachesa predetermined limit. Otherwise, however, the container fills fullywith liquid phase of the fluid, the back pressure P3 suddenly increaseswhen the container is full, equalising with the delivery pressure P1marked F in FIG. 10. However, during the initial mixed vapour/liquidfilling phase indicated at A in FIG. 8, as more fluid is provided to thecontainer, at some point, the vapour pressure increases as thetemperature therein increases and eventually the back pressure in thecylinder equalises with the delivery pressure, so that the fluid flowrate commensurately diminishes towards zero and the delivery pressure P1needs to be increased.

Accordingly, the control means 710 interprets a diminishing fluid flowrate sensed by the fluid flow rate sensing means 730 as indicating thatthe back pressure P3 from the container is increasing, and thus sends anappropriate signal to the pressure regulating means 720 to increase thedelivery pressure P1 of the fluid. Thus, part A of FIG. 8, rather thanbeing a smooth gradient may comprise a wavy profile as the deliverypressure P1 is changed in small increments according to changes in themeasured mass flow.

Thus, in this manner, the control means 710 continually monitors thefluid flow rate measured by the fluid flow sensing means 730, andcontinually increases in very small steps the delivery pressure P1provided by the pressure regulating means 720 whenever the fluid flowrate decreases. Thus, preferably, the control means 710 attempts tomaintain a constant fluid flow rate into the container, or alternativelywithin an upper flow rate limit and a lower flow rate limit. Preferably,though, the control means 710 attempts to maximise the fluid flow rateinto the container 500.

If for any reason the pressure regulating means 720 increases thedelivery pressure P1 by too much, this leads to the valve member 70closing the outlet port 40, and thus the fluid flow rate suddenly dropsto zero. A zero fluid flow measured by the fluid flow sensing means 730is always interpreted by the control means 710 to signify that the valvemember 70 has closed, and under the circumstances i.e. when part of thecontainer has already been filled, the control means 710 commands thepressure regulating means 720 to reduce the delivery pressure. However,when the fluid is a gas with low liquefaction point such as CO₂ forexample, the flow sensing means 730 may be sensitive only to the flow ofliquid and not to the flow of gas. Thus, at the beginning of the fillingoperation, marked A in FIG. 8, when only gas is flowing into thecontainer 500, the flow sensing means will not sense any flow. However,the control means 710 can be programmed for this. Only once some liquidhas formed in the container, then liquid flows through the flow sensingmeans 730, which then senses the flow.

At the same time, an optional pressure release valve 740 releasespressure between the pressure regulating means 720 and the chamber 50 ofthe valve 10, and fluid therein is vented into the atmosphere or tooptional overflow tank 750. Thus, the pressure release valve 740 isoperatively connected to and controlled by, the control means 710 andoperation of the pressure release valve 740 is discontinued when thepressure P2 in the valve 10, in particular in the chamber 50, hasreduced sufficiently such as to enable the valve member 70 to open theoutlet port 40. The delivery pressure P1 to the valve 10 can beadvantageously monitored by means of an optical pressure transducer orother pressure sensor means 760, preferably disposed downstream of thepressure regulating means 720, and operatively connected to the controlmeans 710. Once the static pressure in the valve has been sufficientlyreduced, such as to open the valve member 70, fluid will once again flowinto the container 500, and the control means 710 continues to increasethe delivery pressure P1 of the pressure regulating means 720, as hereinbefore described. Preferably, prior to filling a container 500, thepressure release valve 740 releases pressure between the pressureregulating means 720 and the chamber 50 of the valve 10.

1. A valve for closing a container and for enabling the container to be filled, said valve comprising a housing with an inlet port and an outlet port wherein said inlet port is adapted for connection to a fluid source, said connection being selected from the group of indirect and direct connections, and wherein said outlet port is adapted for connection to said container said connection being selected from the group of indirect and direct connections; a closing member for said outlet port; and at least one valve member which in a first position allows fluid communication between said inlet port and said outlet port and which, in a second position, prevents fluid communication from said inlet port to said outlet port, wherein said valve member is separate from the closing member and is brought into and maintained in said first position only if a static pressure difference across said valve member is below a predeterminable first threshold.
 2. A valve according to claim 1, wherein said valve member has force-generating means adapted for providing a balancing force to said valve member and for bringing said valve member into said first position when said filling condition is fulfilled.
 3. A valve according to claim 2, wherein said force-generating means have a spring.
 4. A valve according to claim 1, wherein the valve member has an internal part comprised in said valve which can be operatively connected with an external part external to said valve for bringing and maintaining said valve member into said first position.
 5. A valve according to claim 4, wherein said internal part has a first magnet or a magnetisable element providing a balancing force for bringing said valve member into said first position when said valve is brought into proximity with an external part having a second magnet.
 6. A valve according to claim 1, wherein said closing member is formed as a check valve.
 7. A valve according to claim 6, wherein said check valve and said valve member are formed on a body movable in a chamber of said housing between said inlet port and said outlet port.
 8. A valve according to claim 6, wherein said check valve comprises a pin attached to an end of said check valve directed towards said inlet port.
 9. A valve according to claim 7, wherein said housing has a chamber divided in to an upstream chamber and a downstream chamber in communication with one another, wherein said upstream chamber is adapted for reciprocatingly accommodating said closing member, and wherein said downstream chamber is adapted for reciprocatingly accommodating said valve member at least between said first and second position.
 10. A valve according to claim 5, wherein said downstream chamber is adapted for aligning movement of said valve member in the direction of magnetic attraction or repulsion between said internal part and said external part.
 11. A system for filling a container with a fluid exclusively from an authorised fluid source, comprising a pressure regulating means in fluid communication to said fluid source and adapted for connection with a valve on said container, said valve comprising a housing with an inlet port and an outlet port wherein said inlet port is adapted for direct or indirect connection to a fluid source and wherein said outlet port is adapted for direct or indirect connection to said container; a closing member for said outlet port; and at least one valve member which in a first position allows fluid communication between said inlet port and said outlet port and which, in a second position, prevents fluid communication from said inlet port to said outlet port, wherein said valve member is brought into and maintained in said first position only if a static pressure difference across said valve member is below a predeterminable first threshold; wherein said pressure regulating means is designed to maintain the pressure of the fluid supplied to said container below a predetermined or predeterminable first threshold selected in such a way that said valve member of said valve is brought into and maintained in said first position.
 12. A system according to claim 11, wherein said system has fluid flow rate sensing means for measuring the flow of liquid into said container, said system further comprising control means operatively connected to said pressure regulating means and said fluid flow rate sensor means.
 13. A system according to claim 12, wherein said pressure regulating means is adapted for providing a delivery pressure of a predetermined minimum magnitude and for increasing the delivery pressure in a manner controllable via said control means.
 14. A system according to claim 12, wherein during operation of the system relating to the filling of a container from a fluid source (699) connected to that system, said control means initially commands the pressure regulation means to provide a delivery pressure of a magnitude below a first predetermined threshold value and then to increase the delivery pressure, maintaining the fluid flow rate within a predetermined range.
 15. A system according to claim 11, wherein the system further comprises an external part of said force-generating means which can be brought in operative connection with an internal part) of a force-generating means said valve for bringing and maintaining said valve member into said first position.
 16. A system according to claim 12, wherein the system comprises means for weighing said container, said means for weighing being coupled to said control means.
 17. A refillable container for storing fluids, wherein said container is provided with a valve, said valve comprising a housing with an inlet port and an outlet port wherein said inlet port is adapted for direct or indirect connection to a fluid source and wherein said outlet port is adapted for direct or indirect connection to said container; a closing member for said outlet port; and at least one valve member which in a first position allows fluid communication between said inlet port and said outlet port and which, in a second position, prevents fluid communication from said inlet port to said outlet port, wherein said valve member is brought into and maintained in said first position only if a static pressure difference across said valve member is below a predeterminable first threshold.
 18. A container according to claim 17, wherein the valve is permanently connected to an opening of said container.
 19. A method for filling a container having a valve with a fluid from a fluid source, said valve comprising a housing with an inlet port and an outlet port wherein said inlet port is adapted for direct or indirect connection to a fluid source and wherein said outlet port is adapted for direct or indirect connection to said container; a closing member for said outlet port; and at least one valve member which in a first position allows fluid communication between said inlet port and said outlet port and which, in a second position, prevents fluid communication from said inlet port to said outlet port, wherein said valve member is brought into and maintained in said first position only if a static pressure difference across said valve member is below a predeterminable first threshold; the method comprising the steps of: a) connecting the valve to said fluid source b) controlling the delivery pressure of said fluid at said inlet port of said valve such as to maintain the static pressure difference across a valve member of said valve below a predetermined or predeterminable first threshold.
 20. A method according to claim 19, wherein step b) comprises the sub-steps of b1) initially providing a static delivery pressure to said inlet port of said valve that is less than a predetermined second threshold during a predetermined or predeterminable period of time b2) after step b1, increasing said delivery pressure continuously or in a plurality of steps.
 21. A method according to claim 19, wherein step b comprises the sub-steps of b3) initially providing a delivery static pressure to said inlet port which is less than a second threshold value b4) measuring the fluid flow rate of fluid flowing into said valve b5) if said fluid flow rate is decreasing, then increasing the magnitude of said delivery static pressure in a predetermined or predeterminable manner b6) continuing steps b4 and b5 until the measured fluid rate is zero.
 22. A method according to claim 19, wherein step b) comprises the further sub steps of b7) measuring the static pressure at said inlet port b8) if said static pressure in said step is within a predetermined third threshold value of the magnitude of the pressure of the container when full, discontinuing filling of container and disconnecting the valve from said fluid source b9) if said static pressure in step b7) is less than a predetermined third threshold value of the magnitude of the pressure of the container when full, discontinuing filling of container, releasing pressure in the valve upstream of the outlet port, resuming filling of container and continuing with steps b7) to b8).
 23. A method according to claim 19, wherein before and/or during the filling procedure, the weight of the container is continuously measured. 